Question

As per indian calendar,during which month is the festival of Diwali celebration

Answer 1

Kartika
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As per indian calendar , the festival of Diwali celebration comes in karthik mas (month)
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Diwali comes on the new moon night of karthik mas , as there will be darkness everywhere at that time we will light diyas and burn crackers etc .

This karthic mas usually falls in the month of october or november of the international calendar , this date varies . 

There is something called Adhik Maas , if there is adhik maas in a particular year them the festival will be postponed to 1 month at this time diwali may end up in november 

Answer 2

Kartiaka
As in the Indian calendar Diwali is celebrated in kartiaka month (mas)
It always take place in the month of October and November by the International calendar.
This come on the new moon night of kartika mas as there's darkness in the whole sky . So crackers , Ligth , and diya are ligthed.